Hookworms, scientific names Ancylostoma caninum and
Ancylostoma braziliense, affect twenty percent of adult dogs.
They are the most prevalent worm infecting dogs. Dogs become
infected by eating the larvae in contaminated water and/or
soil, by eating another host animal or by the larvae getting
in through the skin. Hookworms are like roundworms and can
be transmitted to puppies from the mother dog through the
placenta and from mammary milk.

Hookworms can also infect humans and cats. In most cases
they infect the intestines by using their teeth to hook into
the intestinal wall and they feed off of the host animal's
blood. If the hookworm infection is really bad and the host
is a puppy it can result in death from anemia.

Hookworms can only be transmitted through infected feces or
soil where infected feces have been. The larvae can last for
a very long time until a suitable host comes along to pick
it up. It is very important to not walk your dog where there
may be unsanitary conditions with a lot of feces.

But a dog can also get hookworms through other animals that
it eats such as rodents, squirrels, cats and other small
animals.

A Hookworm's Lifecycle

Hookworms are totally dependent on their hosts. A pair of
hookworms in a host mate and release eggs that go out
through the feces of the infected animal. It then takes five
days for the eggs to go through three stages of development
to become larvae so that they can then wait to infect a host
animal.

The three stages are egg, hatchling and then larvae.

Once the larvae is picked up by a new host they will make
their way back down to the intestine either through being
eaten or by burrowing through the skin. In some cases the
hookworm will, instead of staying in the intestine, travel
to the lung tissue and feed there until they reach the
fourth stage of maturity. Then they will crawl up the
trachea, causing the host to cough and then swallow it again
where it will go back down into the intestine to complete
its life cycle.

Occasionally if the host is a pregnant canine the hookworm
will instead be redirected to the placenta because of the
hormones associated with pregnancy and infects the pups or
infects the puppies through the mammary glands.